Pumping devices and systems for moving quantities of fluids are known and employed in a great many contexts. Most pumping devices and systems may be categorized as positive displacement or dynamic. Positive displacement pumps and systems, in turn, may be categorized as reciprocating or rotary. Regardless of their classification, known pumping devices and systems suffer from a number of deficiencies that render them either inefficient or inoperable in some contexts.
Syringe pumps, for example, require operation of a piston, moved by a gear or similar mechanism, rendering the pumps subject to mechanical failure. In addition, altering the volume pumped or other parameters requires manipulation of the mechanism. Peristaltic pumps similarly rely on an external mechanism to provide the force necessary to move a fluid.
An electroosmotic pump, considered a dynamic pump, does not move fluids by mechanically-generated forces and therefore does not suffer from some of the deficiencies associated with such external mechanisms. However, electroosmotic pumps require the application of an electric field to the fluid, imparting significant limitations and inefficiencies to their operation. Electroosmotic pumps also tend to result in very high pressures (up to about 5,000 PSI) and/or flow rates, rendering them unsuitable for some applications.
Pressure pumps similarly do not necessarily rely on a mechanical force during their operation. Instead, pressure pumps rely on a reservoir of fluid stored under pressure and the operation of a valve or similar device for controlling fluid flow from the reservoir. Some mechanical force is generally employed, however, in pressurizing fluid within the reservoir. In addition, the pressure and/or flow rate achievable using a pressure pump is dependent upon the pressure within the reservoir, which generally decreases as fluid is drained from it.